The invention set forth in this specification pertains to a new and improved grinding apparatus and method. More specifically it pertains to the use of material movement during grinding to promote the flow of such material to between grinding wheels.
The use of grinding wheels or disks is considered to be virtually as old as civilization itself. In a grinding apparatus in which such wheels are used an appropriate apparatus or means is used to cause relative rotation between the wheels. Such an apparatus normally employs a feed hopper for holding the material to be ground and for conveying such material to an inlet opening located in one of the wheels and leading to a space generally between the wheels. As an apparatus of this type is operated so that there is relative rotation between the wheels the movement of the wheels normally causes the movement of such material generally between opposed peripheral comminution surfaces on the wheels.
Obviously a grinding apparatus utilizing the parts indicated in the preceding can be constructed in many different ways, and can be utilized for grinding many different types of materials. In some uses of a grinding apparatus having the parts as noted problems have been encountered in feeding the material to be ground from the hopper to generally between the grinding wheels or disks. In some cases such problems are primarily the result of the material within the hopper not flowing by gravity to generally between the wheels or disks. In some cases the reverse movement of material from generally between the wheels or disks back toward the hopper caused by the operation of the wheels or disks tends to interfere with the desired movement of material toward the wheels or disks.
When a grinding apparatus as noted is constructed or operated in such a manner that such reverse movement or kickback of material being ground is encountered the character of the material kicked back may cause an additional impediment to the desired flow of the material from the hopper to generally between the grinding wheels or disks. This can be illustrated in connection with a grinding apparatus utilizing a lower grinding disk rotated at comparatively high speed relative to a stationary grinding disk having an upwardly directed opening in communication with a feed hopper. When such an apparatus is used with certain types of nuts the material kicked back through the opening generally toward the hopper on occasion will tend to be somewhat sticky or gummy as a result of being partially comminuted. This stickiness will in effect cause a further interference with the flow of the feed material to be ground generally between the wheels or disks.
As a result of these factors it is known to utilize an agitator or agitator structure within a feed hopper of a grinding apparatus as described in order to constantly agitate the material in such a hopper so as to constantly cause it to move toward the grinding wheels at a desired rate. A wide variety of such agitators have been proposed and used. It is considered undersirable in many types of grinding apparatus to utilize an agitator which is mechanically operated so as to cause agitation of the feed material because of the cost and relative complexity of a mechanically driven agitator.
Hand actuated agitators have also been proposed and used. It is considered that these are not overly acceptable because the user of a grinding apparatus in which relative movement between the grinding wheels is caused mechanically through an appropriate motor or the like normally will not be satisfied in having to constantly monitor the operation of the grinding apparatus so as to actuate a hand operated actuator as required.